Oven Floor issue

[Pizza Freak]

Hi All,
I finally got my Casa 90 yesterday, and before I fully commit to my floor construction, I just want to verify my thinking.

My plan is to put a layer of FB board down on my slab, next put a layer of low duty fire brick (so we're at 4.5" high now off the slab...2" of FB board plus 2.5" of firebrick), construct the forno bravo cooking floor on top of the fire bricks, and then position the two halves of the oven around the cooking floor. The bottom edges of the oven will be in contact with the fire bricks, of course.

I've noticed that a lot of people using FB board or SuperIsol will just put the forno bravo cooking floor on top of the insulation, without the layer of firebrick. My thinking is that the firebrick will give me a little more mass and will hold/reradiate heat longer. My only concern is the possibility of heat "leaking" out the sides of the firebricks, since they are insulated only on the bottom (by the FB board). Or is that a non-issue?

I should mention that all of this will be enclosed in a gable house.

Am I on the right track, or are the fire bricks overkill?

Thanks!

[Les]

I'm thinking overkill with the firebrick (unless you need the height). If the Casa needed a thicker floor, I believe James would have made it so.

Les...

[DrakeRemoray]

Most of us do not have experience with the precast ovens, so hopefully James will chime in, but my thought is if you are addning that much mass to the floor, are you planning to add additional mass to the dome as well? In my experience, the dome mass charges up the floor, not the other way around...

Drake

[james]

Hey all,

FB recommends putting the Casa (Premio or Artigiano) cooking floor directly on the insulating layer -- either FB Board or vermiculite concrete. The thickness of the floor is heavy enough for home baking and it also tuned to the thickness of the dome.

It turns out that keeping the cooking floor hot enough for cooking pizza and in balance with the heat of the oven dome is one of the trickier parts of oven management, and building up the mass of the floor will make it even trickier. The reason is that the thicker floor mass will effectively wick heat away from the top of floor (where you want it for high heat cooking) to the outer edge of the mass (the bottom, where is will be stored for low heat baking later).

The amount of mass in the Casa floor is definitely high enough for bread baking and roasting. You'll love it!

I think this graphic does a pretty good job of capturing the way your oven works and why it is as thick as it is.
James

[james]

Christo pointed out (correctly) that the graphic isn't clear which part of the oven are which.

I have labeled the oven dome and oven floor in this version. Does this work better? More clear?

James

[Pizza Freak]

Thanks All,
James, your graphic makes the point and I'll skip the fire brick. It makes my life easier!
The fire bricks, intuitively, seemed like a real heat sink, but it was suggested to me as a good idea.
The oven floor gets mortared tomorrow, and if my wife has a strong enough back, we'll put the two sections of the casa in place on Thursday.

I can already smell the pizza!

Thanks,
PF